Read the article and therein is the problem. AMA racing stars signing autographs to attract a crowd. The nuisance of backyard motocross tracks are exacerbated by all of the juvinile AMA supercross wannabees riding around in circles for hours on end in the backyard, every day!
Picture this activity going on next to YOUR house and one can understand why the Riverside county Supervisors are supporting increased restrictions on this activity. People have a reasonable right to enjoy peace and quiet in their homes.